New Source Review: Modeling and Offsets

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New Source ReviewModeling and Offsets
November 2, 2005
Judy B. Yorke Yorke Engineering, LLC 949-248-8490
x25 JYorke_at_YorkeEngr.com
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NSR Modeling Requirement

• A demonstration that the new/modified source will
  not cause a violation, or make significantly
  worse an existing violation of the NAAQS.
• Exemptions are identified in Rule 1304, for
  example
• Replacements
• Emergency Equipment and
• Air Pollution Control

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NSR Modeling Demonstration

• SCAQMD Rule 1303 Appendix A
• Screening Analysis
• If hourly emissions are less than the values in
  Table A-1, the modeling requirement is satisfied
• If source does not pass screening analysis,
  detailed modeling is required

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Table A-1 Allowable Emissions
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Detailed Air Quality Modeling

• Create dispersion model using SCREEN3 or ISCST3
• Calculate highest pollutant concentration for
  receptors outside facility boundary
• 1-hour average
• Annual average
• Determine ambient pollutant concentration by
  taking highest value from most recent 3 years
  data
• Add new concentration to ambient concentration
• Modeling satisfied if sum does not exceed values
  in Table A-2.

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TABLE A-2 Most Stringent AAQS
pphm parts per hundred million
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NSR-Offsets

• Goal of Offsets
• Use emission reductions from existing sources to
  offset emission increases
• Reductions more than compensate for increases and
  result in a net air quality benefit

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Offset Ratio

• Generally, offsets are required at a 1.2-to-1
  ratio
• Some variations, e.g.,
• Priority Reserve
• Offset Budget
• RECLAIM NOx/SOx

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Offset Exemptions

• Exemptions are identified in Rule 1304, for
  example
• Qualifying Replacements
• Emergency Equipment
• Air Pollution Controls
• Relocations
• Facilities with a PTE below thresholds

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NSR-Offset Exemption Thresholds
Offsets are required if facility exceeds
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Cost of Offsets

• The cost of offsets vary with the demand
• Examples of market prices, current bids/offers
•          Non-RECLAIM Emission Reduction Credits
  -
• o       PM10 65,000/lb
• o       ROG 1,500/lb
• o       CO 7,800/lb
•          RECLAIM Trading Credits -
• o       NOx .75-2.5/lb
• o       SOx 1.35-3.5/lb

From Christine Grandstaff of Cantor Fitzgerald
(949-240-4602)
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Generating ERCs

• Rule 1309 defines requirements to obtain ERCs
• Rule 1306 the emission decrease which may be
  considered
• Requirements are very stringent

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To Obtain ERCs

• 2 years of records demonstrating actual emissions
  must be provided
• Actual emissions are discounted to current BACT
  emission rate
• Discounted emissions are further cut by usage
  factor if operated less than 180 days/year.

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Summary

• Review carefully BACT determination
• Review offset and modeling applicability and
  requirements
• Check permit conditions carefully
• Get help when you need help!